fuel additives: helpful or waste of money?

[knoll5150]

Does anyone out their have any concrete opinions (i.e their own experiences, not stuff they read from the manufacturers) on the effectiveness of using fuel additives on their car's that supposedly clean out the injectors and clean the engine of "gunk" to help with performance/fuel economy. I've heard most major brands of gas allready have these additives in their fuel, making the additives you can get off the shelf a waste of money. Just wondering if anyone out their has had any sucess with any of these products. After the Slick50 scam a few years back, I'm somewhat skeptikal of these poducts now.

[rapter34]

use seafoam great product that goes in the gas, oil, and the intake. cleans out all the carbon out of your engine. search the site the find out more about it.

[Sarge]

I go by analysis from Southwest Research Institute and Terry Dyson only....not the butt dyno nor internet bullshit.
I only recommend Lucas UCL.